Powder Pre-Conditioning for the LS Process

It has previously been shown that the use of recycled Nylon-12 powder leads to increased Elongation at Break (EaB) of Laser Sintered (LS) parts, possibly due to elevated powder temperature in the part bed causing increases in molecular weight. However, this increase in EaB often corresponds to a decrease in repeatability, likely to be through variations in powder history. The research presented here has shown that thermal pre-conditioning of virgin powder can increase EaB of LS parts, with no significant loss of repeatability. Materials analysis of the conditioned powder batches is also presented in order to quantify the differences in powder properties and to help explain the mechanisms involved.